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Linux/arch/sparc/mm/tsb.c

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /* arch/sparc64/mm/tsb.c
  3  *
  4  * Copyright (C) 2006, 2008 David S. Miller <davem@davemloft.net>
  5  */
  6 
  7 #include <linux/kernel.h>
  8 #include <linux/preempt.h>
  9 #include <linux/slab.h>
 10 #include <linux/mm_types.h>
 11 
 12 #include <asm/page.h>
 13 #include <asm/pgtable.h>
 14 #include <asm/mmu_context.h>
 15 #include <asm/setup.h>
 16 #include <asm/tsb.h>
 17 #include <asm/tlb.h>
 18 #include <asm/oplib.h>
 19 
 20 extern struct tsb swapper_tsb[KERNEL_TSB_NENTRIES];
 21 
 22 static inline unsigned long tsb_hash(unsigned long vaddr, unsigned long hash_shift, unsigned long nentries)
 23 {
 24         vaddr >>= hash_shift;
 25         return vaddr & (nentries - 1);
 26 }
 27 
 28 static inline int tag_compare(unsigned long tag, unsigned long vaddr)
 29 {
 30         return (tag == (vaddr >> 22));
 31 }
 32 
 33 static void flush_tsb_kernel_range_scan(unsigned long start, unsigned long end)
 34 {
 35         unsigned long idx;
 36 
 37         for (idx = 0; idx < KERNEL_TSB_NENTRIES; idx++) {
 38                 struct tsb *ent = &swapper_tsb[idx];
 39                 unsigned long match = idx << 13;
 40 
 41                 match |= (ent->tag << 22);
 42                 if (match >= start && match < end)
 43                         ent->tag = (1UL << TSB_TAG_INVALID_BIT);
 44         }
 45 }
 46 
 47 /* TSB flushes need only occur on the processor initiating the address
 48  * space modification, not on each cpu the address space has run on.
 49  * Only the TLB flush needs that treatment.
 50  */
 51 
 52 void flush_tsb_kernel_range(unsigned long start, unsigned long end)
 53 {
 54         unsigned long v;
 55 
 56         if ((end - start) >> PAGE_SHIFT >= 2 * KERNEL_TSB_NENTRIES)
 57                 return flush_tsb_kernel_range_scan(start, end);
 58 
 59         for (v = start; v < end; v += PAGE_SIZE) {
 60                 unsigned long hash = tsb_hash(v, PAGE_SHIFT,
 61                                               KERNEL_TSB_NENTRIES);
 62                 struct tsb *ent = &swapper_tsb[hash];
 63 
 64                 if (tag_compare(ent->tag, v))
 65                         ent->tag = (1UL << TSB_TAG_INVALID_BIT);
 66         }
 67 }
 68 
 69 static void __flush_tsb_one_entry(unsigned long tsb, unsigned long v,
 70                                   unsigned long hash_shift,
 71                                   unsigned long nentries)
 72 {
 73         unsigned long tag, ent, hash;
 74 
 75         v &= ~0x1UL;
 76         hash = tsb_hash(v, hash_shift, nentries);
 77         ent = tsb + (hash * sizeof(struct tsb));
 78         tag = (v >> 22UL);
 79 
 80         tsb_flush(ent, tag);
 81 }
 82 
 83 static void __flush_tsb_one(struct tlb_batch *tb, unsigned long hash_shift,
 84                             unsigned long tsb, unsigned long nentries)
 85 {
 86         unsigned long i;
 87 
 88         for (i = 0; i < tb->tlb_nr; i++)
 89                 __flush_tsb_one_entry(tsb, tb->vaddrs[i], hash_shift, nentries);
 90 }
 91 
 92 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
 93 static void __flush_huge_tsb_one_entry(unsigned long tsb, unsigned long v,
 94                                        unsigned long hash_shift,
 95                                        unsigned long nentries,
 96                                        unsigned int hugepage_shift)
 97 {
 98         unsigned int hpage_entries;
 99         unsigned int i;
100 
101         hpage_entries = 1 << (hugepage_shift - hash_shift);
102         for (i = 0; i < hpage_entries; i++)
103                 __flush_tsb_one_entry(tsb, v + (i << hash_shift), hash_shift,
104                                       nentries);
105 }
106 
107 static void __flush_huge_tsb_one(struct tlb_batch *tb, unsigned long hash_shift,
108                                  unsigned long tsb, unsigned long nentries,
109                                  unsigned int hugepage_shift)
110 {
111         unsigned long i;
112 
113         for (i = 0; i < tb->tlb_nr; i++)
114                 __flush_huge_tsb_one_entry(tsb, tb->vaddrs[i], hash_shift,
115                                            nentries, hugepage_shift);
116 }
117 #endif
118 
119 void flush_tsb_user(struct tlb_batch *tb)
120 {
121         struct mm_struct *mm = tb->mm;
122         unsigned long nentries, base, flags;
123 
124         spin_lock_irqsave(&mm->context.lock, flags);
125 
126         if (tb->hugepage_shift < REAL_HPAGE_SHIFT) {
127                 base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
128                 nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
129                 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
130                         base = __pa(base);
131                 if (tb->hugepage_shift == PAGE_SHIFT)
132                         __flush_tsb_one(tb, PAGE_SHIFT, base, nentries);
133 #if defined(CONFIG_HUGETLB_PAGE)
134                 else
135                         __flush_huge_tsb_one(tb, PAGE_SHIFT, base, nentries,
136                                              tb->hugepage_shift);
137 #endif
138         }
139 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
140         else if (mm->context.tsb_block[MM_TSB_HUGE].tsb) {
141                 base = (unsigned long) mm->context.tsb_block[MM_TSB_HUGE].tsb;
142                 nentries = mm->context.tsb_block[MM_TSB_HUGE].tsb_nentries;
143                 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
144                         base = __pa(base);
145                 __flush_huge_tsb_one(tb, REAL_HPAGE_SHIFT, base, nentries,
146                                      tb->hugepage_shift);
147         }
148 #endif
149         spin_unlock_irqrestore(&mm->context.lock, flags);
150 }
151 
152 void flush_tsb_user_page(struct mm_struct *mm, unsigned long vaddr,
153                          unsigned int hugepage_shift)
154 {
155         unsigned long nentries, base, flags;
156 
157         spin_lock_irqsave(&mm->context.lock, flags);
158 
159         if (hugepage_shift < REAL_HPAGE_SHIFT) {
160                 base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
161                 nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
162                 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
163                         base = __pa(base);
164                 if (hugepage_shift == PAGE_SHIFT)
165                         __flush_tsb_one_entry(base, vaddr, PAGE_SHIFT,
166                                               nentries);
167 #if defined(CONFIG_HUGETLB_PAGE)
168                 else
169                         __flush_huge_tsb_one_entry(base, vaddr, PAGE_SHIFT,
170                                                    nentries, hugepage_shift);
171 #endif
172         }
173 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
174         else if (mm->context.tsb_block[MM_TSB_HUGE].tsb) {
175                 base = (unsigned long) mm->context.tsb_block[MM_TSB_HUGE].tsb;
176                 nentries = mm->context.tsb_block[MM_TSB_HUGE].tsb_nentries;
177                 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
178                         base = __pa(base);
179                 __flush_huge_tsb_one_entry(base, vaddr, REAL_HPAGE_SHIFT,
180                                            nentries, hugepage_shift);
181         }
182 #endif
183         spin_unlock_irqrestore(&mm->context.lock, flags);
184 }
185 
186 #define HV_PGSZ_IDX_BASE        HV_PGSZ_IDX_8K
187 #define HV_PGSZ_MASK_BASE       HV_PGSZ_MASK_8K
188 
189 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
190 #define HV_PGSZ_IDX_HUGE        HV_PGSZ_IDX_4MB
191 #define HV_PGSZ_MASK_HUGE       HV_PGSZ_MASK_4MB
192 #endif
193 
194 static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_idx, unsigned long tsb_bytes)
195 {
196         unsigned long tsb_reg, base, tsb_paddr;
197         unsigned long page_sz, tte;
198 
199         mm->context.tsb_block[tsb_idx].tsb_nentries =
200                 tsb_bytes / sizeof(struct tsb);
201 
202         switch (tsb_idx) {
203         case MM_TSB_BASE:
204                 base = TSBMAP_8K_BASE;
205                 break;
206 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
207         case MM_TSB_HUGE:
208                 base = TSBMAP_4M_BASE;
209                 break;
210 #endif
211         default:
212                 BUG();
213         }
214 
215         tte = pgprot_val(PAGE_KERNEL_LOCKED);
216         tsb_paddr = __pa(mm->context.tsb_block[tsb_idx].tsb);
217         BUG_ON(tsb_paddr & (tsb_bytes - 1UL));
218 
219         /* Use the smallest page size that can map the whole TSB
220          * in one TLB entry.
221          */
222         switch (tsb_bytes) {
223         case 8192 << 0:
224                 tsb_reg = 0x0UL;
225 #ifdef DCACHE_ALIASING_POSSIBLE
226                 base += (tsb_paddr & 8192);
227 #endif
228                 page_sz = 8192;
229                 break;
230 
231         case 8192 << 1:
232                 tsb_reg = 0x1UL;
233                 page_sz = 64 * 1024;
234                 break;
235 
236         case 8192 << 2:
237                 tsb_reg = 0x2UL;
238                 page_sz = 64 * 1024;
239                 break;
240 
241         case 8192 << 3:
242                 tsb_reg = 0x3UL;
243                 page_sz = 64 * 1024;
244                 break;
245 
246         case 8192 << 4:
247                 tsb_reg = 0x4UL;
248                 page_sz = 512 * 1024;
249                 break;
250 
251         case 8192 << 5:
252                 tsb_reg = 0x5UL;
253                 page_sz = 512 * 1024;
254                 break;
255 
256         case 8192 << 6:
257                 tsb_reg = 0x6UL;
258                 page_sz = 512 * 1024;
259                 break;
260 
261         case 8192 << 7:
262                 tsb_reg = 0x7UL;
263                 page_sz = 4 * 1024 * 1024;
264                 break;
265 
266         default:
267                 printk(KERN_ERR "TSB[%s:%d]: Impossible TSB size %lu, killing process.\n",
268                        current->comm, current->pid, tsb_bytes);
269                 do_exit(SIGSEGV);
270         }
271         tte |= pte_sz_bits(page_sz);
272 
273         if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
274                 /* Physical mapping, no locked TLB entry for TSB.  */
275                 tsb_reg |= tsb_paddr;
276 
277                 mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg;
278                 mm->context.tsb_block[tsb_idx].tsb_map_vaddr = 0;
279                 mm->context.tsb_block[tsb_idx].tsb_map_pte = 0;
280         } else {
281                 tsb_reg |= base;
282                 tsb_reg |= (tsb_paddr & (page_sz - 1UL));
283                 tte |= (tsb_paddr & ~(page_sz - 1UL));
284 
285                 mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg;
286                 mm->context.tsb_block[tsb_idx].tsb_map_vaddr = base;
287                 mm->context.tsb_block[tsb_idx].tsb_map_pte = tte;
288         }
289 
290         /* Setup the Hypervisor TSB descriptor.  */
291         if (tlb_type == hypervisor) {
292                 struct hv_tsb_descr *hp = &mm->context.tsb_descr[tsb_idx];
293 
294                 switch (tsb_idx) {
295                 case MM_TSB_BASE:
296                         hp->pgsz_idx = HV_PGSZ_IDX_BASE;
297                         break;
298 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
299                 case MM_TSB_HUGE:
300                         hp->pgsz_idx = HV_PGSZ_IDX_HUGE;
301                         break;
302 #endif
303                 default:
304                         BUG();
305                 }
306                 hp->assoc = 1;
307                 hp->num_ttes = tsb_bytes / 16;
308                 hp->ctx_idx = 0;
309                 switch (tsb_idx) {
310                 case MM_TSB_BASE:
311                         hp->pgsz_mask = HV_PGSZ_MASK_BASE;
312                         break;
313 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
314                 case MM_TSB_HUGE:
315                         hp->pgsz_mask = HV_PGSZ_MASK_HUGE;
316                         break;
317 #endif
318                 default:
319                         BUG();
320                 }
321                 hp->tsb_base = tsb_paddr;
322                 hp->resv = 0;
323         }
324 }
325 
326 struct kmem_cache *pgtable_cache __read_mostly;
327 
328 static struct kmem_cache *tsb_caches[8] __read_mostly;
329 
330 static const char *tsb_cache_names[8] = {
331         "tsb_8KB",
332         "tsb_16KB",
333         "tsb_32KB",
334         "tsb_64KB",
335         "tsb_128KB",
336         "tsb_256KB",
337         "tsb_512KB",
338         "tsb_1MB",
339 };
340 
341 void __init pgtable_cache_init(void)
342 {
343         unsigned long i;
344 
345         pgtable_cache = kmem_cache_create("pgtable_cache",
346                                           PAGE_SIZE, PAGE_SIZE,
347                                           0,
348                                           _clear_page);
349         if (!pgtable_cache) {
350                 prom_printf("pgtable_cache_init(): Could not create!\n");
351                 prom_halt();
352         }
353 
354         for (i = 0; i < ARRAY_SIZE(tsb_cache_names); i++) {
355                 unsigned long size = 8192 << i;
356                 const char *name = tsb_cache_names[i];
357 
358                 tsb_caches[i] = kmem_cache_create(name,
359                                                   size, size,
360                                                   0, NULL);
361                 if (!tsb_caches[i]) {
362                         prom_printf("Could not create %s cache\n", name);
363                         prom_halt();
364                 }
365         }
366 }
367 
368 int sysctl_tsb_ratio = -2;
369 
370 static unsigned long tsb_size_to_rss_limit(unsigned long new_size)
371 {
372         unsigned long num_ents = (new_size / sizeof(struct tsb));
373 
374         if (sysctl_tsb_ratio < 0)
375                 return num_ents - (num_ents >> -sysctl_tsb_ratio);
376         else
377                 return num_ents + (num_ents >> sysctl_tsb_ratio);
378 }
379 
380 /* When the RSS of an address space exceeds tsb_rss_limit for a TSB,
381  * do_sparc64_fault() invokes this routine to try and grow it.
382  *
383  * When we reach the maximum TSB size supported, we stick ~0UL into
384  * tsb_rss_limit for that TSB so the grow checks in do_sparc64_fault()
385  * will not trigger any longer.
386  *
387  * The TSB can be anywhere from 8K to 1MB in size, in increasing powers
388  * of two.  The TSB must be aligned to it's size, so f.e. a 512K TSB
389  * must be 512K aligned.  It also must be physically contiguous, so we
390  * cannot use vmalloc().
391  *
392  * The idea here is to grow the TSB when the RSS of the process approaches
393  * the number of entries that the current TSB can hold at once.  Currently,
394  * we trigger when the RSS hits 3/4 of the TSB capacity.
395  */
396 void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long rss)
397 {
398         unsigned long max_tsb_size = 1 * 1024 * 1024;
399         unsigned long new_size, old_size, flags;
400         struct tsb *old_tsb, *new_tsb;
401         unsigned long new_cache_index, old_cache_index;
402         unsigned long new_rss_limit;
403         gfp_t gfp_flags;
404 
405         if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
406                 max_tsb_size = (PAGE_SIZE << MAX_ORDER);
407 
408         new_cache_index = 0;
409         for (new_size = 8192; new_size < max_tsb_size; new_size <<= 1UL) {
410                 new_rss_limit = tsb_size_to_rss_limit(new_size);
411                 if (new_rss_limit > rss)
412                         break;
413                 new_cache_index++;
414         }
415 
416         if (new_size == max_tsb_size)
417                 new_rss_limit = ~0UL;
418 
419 retry_tsb_alloc:
420         gfp_flags = GFP_KERNEL;
421         if (new_size > (PAGE_SIZE * 2))
422                 gfp_flags |= __GFP_NOWARN | __GFP_NORETRY;
423 
424         new_tsb = kmem_cache_alloc_node(tsb_caches[new_cache_index],
425                                         gfp_flags, numa_node_id());
426         if (unlikely(!new_tsb)) {
427                 /* Not being able to fork due to a high-order TSB
428                  * allocation failure is very bad behavior.  Just back
429                  * down to a 0-order allocation and force no TSB
430                  * growing for this address space.
431                  */
432                 if (mm->context.tsb_block[tsb_index].tsb == NULL &&
433                     new_cache_index > 0) {
434                         new_cache_index = 0;
435                         new_size = 8192;
436                         new_rss_limit = ~0UL;
437                         goto retry_tsb_alloc;
438                 }
439 
440                 /* If we failed on a TSB grow, we are under serious
441                  * memory pressure so don't try to grow any more.
442                  */
443                 if (mm->context.tsb_block[tsb_index].tsb != NULL)
444                         mm->context.tsb_block[tsb_index].tsb_rss_limit = ~0UL;
445                 return;
446         }
447 
448         /* Mark all tags as invalid.  */
449         tsb_init(new_tsb, new_size);
450 
451         /* Ok, we are about to commit the changes.  If we are
452          * growing an existing TSB the locking is very tricky,
453          * so WATCH OUT!
454          *
455          * We have to hold mm->context.lock while committing to the
456          * new TSB, this synchronizes us with processors in
457          * flush_tsb_user() and switch_mm() for this address space.
458          *
459          * But even with that lock held, processors run asynchronously
460          * accessing the old TSB via TLB miss handling.  This is OK
461          * because those actions are just propagating state from the
462          * Linux page tables into the TSB, page table mappings are not
463          * being changed.  If a real fault occurs, the processor will
464          * synchronize with us when it hits flush_tsb_user(), this is
465          * also true for the case where vmscan is modifying the page
466          * tables.  The only thing we need to be careful with is to
467          * skip any locked TSB entries during copy_tsb().
468          *
469          * When we finish committing to the new TSB, we have to drop
470          * the lock and ask all other cpus running this address space
471          * to run tsb_context_switch() to see the new TSB table.
472          */
473         spin_lock_irqsave(&mm->context.lock, flags);
474 
475         old_tsb = mm->context.tsb_block[tsb_index].tsb;
476         old_cache_index =
477                 (mm->context.tsb_block[tsb_index].tsb_reg_val & 0x7UL);
478         old_size = (mm->context.tsb_block[tsb_index].tsb_nentries *
479                     sizeof(struct tsb));
480 
481 
482         /* Handle multiple threads trying to grow the TSB at the same time.
483          * One will get in here first, and bump the size and the RSS limit.
484          * The others will get in here next and hit this check.
485          */
486         if (unlikely(old_tsb &&
487                      (rss < mm->context.tsb_block[tsb_index].tsb_rss_limit))) {
488                 spin_unlock_irqrestore(&mm->context.lock, flags);
489 
490                 kmem_cache_free(tsb_caches[new_cache_index], new_tsb);
491                 return;
492         }
493 
494         mm->context.tsb_block[tsb_index].tsb_rss_limit = new_rss_limit;
495 
496         if (old_tsb) {
497                 extern void copy_tsb(unsigned long old_tsb_base,
498                                      unsigned long old_tsb_size,
499                                      unsigned long new_tsb_base,
500                                      unsigned long new_tsb_size,
501                                      unsigned long page_size_shift);
502                 unsigned long old_tsb_base = (unsigned long) old_tsb;
503                 unsigned long new_tsb_base = (unsigned long) new_tsb;
504 
505                 if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
506                         old_tsb_base = __pa(old_tsb_base);
507                         new_tsb_base = __pa(new_tsb_base);
508                 }
509                 copy_tsb(old_tsb_base, old_size, new_tsb_base, new_size,
510                         tsb_index == MM_TSB_BASE ?
511                         PAGE_SHIFT : REAL_HPAGE_SHIFT);
512         }
513 
514         mm->context.tsb_block[tsb_index].tsb = new_tsb;
515         setup_tsb_params(mm, tsb_index, new_size);
516 
517         spin_unlock_irqrestore(&mm->context.lock, flags);
518 
519         /* If old_tsb is NULL, we're being invoked for the first time
520          * from init_new_context().
521          */
522         if (old_tsb) {
523                 /* Reload it on the local cpu.  */
524                 tsb_context_switch(mm);
525 
526                 /* Now force other processors to do the same.  */
527                 preempt_disable();
528                 smp_tsb_sync(mm);
529                 preempt_enable();
530 
531                 /* Now it is safe to free the old tsb.  */
532                 kmem_cache_free(tsb_caches[old_cache_index], old_tsb);
533         }
534 }
535 
536 int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
537 {
538         unsigned long mm_rss = get_mm_rss(mm);
539 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
540         unsigned long saved_hugetlb_pte_count;
541         unsigned long saved_thp_pte_count;
542 #endif
543         unsigned int i;
544 
545         spin_lock_init(&mm->context.lock);
546 
547         mm->context.sparc64_ctx_val = 0UL;
548 
549         mm->context.tag_store = NULL;
550         spin_lock_init(&mm->context.tag_lock);
551 
552 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
553         /* We reset them to zero because the fork() page copying
554          * will re-increment the counters as the parent PTEs are
555          * copied into the child address space.
556          */
557         saved_hugetlb_pte_count = mm->context.hugetlb_pte_count;
558         saved_thp_pte_count = mm->context.thp_pte_count;
559         mm->context.hugetlb_pte_count = 0;
560         mm->context.thp_pte_count = 0;
561 
562         mm_rss -= saved_thp_pte_count * (HPAGE_SIZE / PAGE_SIZE);
563 #endif
564 
565         /* copy_mm() copies over the parent's mm_struct before calling
566          * us, so we need to zero out the TSB pointer or else tsb_grow()
567          * will be confused and think there is an older TSB to free up.
568          */
569         for (i = 0; i < MM_NUM_TSBS; i++)
570                 mm->context.tsb_block[i].tsb = NULL;
571 
572         /* If this is fork, inherit the parent's TSB size.  We would
573          * grow it to that size on the first page fault anyways.
574          */
575         tsb_grow(mm, MM_TSB_BASE, mm_rss);
576 
577 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
578         if (unlikely(saved_hugetlb_pte_count + saved_thp_pte_count))
579                 tsb_grow(mm, MM_TSB_HUGE,
580                          (saved_hugetlb_pte_count + saved_thp_pte_count) *
581                          REAL_HPAGE_PER_HPAGE);
582 #endif
583 
584         if (unlikely(!mm->context.tsb_block[MM_TSB_BASE].tsb))
585                 return -ENOMEM;
586 
587         return 0;
588 }
589 
590 static void tsb_destroy_one(struct tsb_config *tp)
591 {
592         unsigned long cache_index;
593 
594         if (!tp->tsb)
595                 return;
596         cache_index = tp->tsb_reg_val & 0x7UL;
597         kmem_cache_free(tsb_caches[cache_index], tp->tsb);
598         tp->tsb = NULL;
599         tp->tsb_reg_val = 0UL;
600 }
601 
602 void destroy_context(struct mm_struct *mm)
603 {
604         unsigned long flags, i;
605 
606         for (i = 0; i < MM_NUM_TSBS; i++)
607                 tsb_destroy_one(&mm->context.tsb_block[i]);
608 
609         spin_lock_irqsave(&ctx_alloc_lock, flags);
610 
611         if (CTX_VALID(mm->context)) {
612                 unsigned long nr = CTX_NRBITS(mm->context);
613                 mmu_context_bmap[nr>>6] &= ~(1UL << (nr & 63));
614         }
615 
616         spin_unlock_irqrestore(&ctx_alloc_lock, flags);
617 
618         /* If ADI tag storage was allocated for this task, free it */
619         if (mm->context.tag_store) {
620                 tag_storage_desc_t *tag_desc;
621                 unsigned long max_desc;
622                 unsigned char *tags;
623 
624                 tag_desc = mm->context.tag_store;
625                 max_desc = PAGE_SIZE/sizeof(tag_storage_desc_t);
626                 for (i = 0; i < max_desc; i++) {
627                         tags = tag_desc->tags;
628                         tag_desc->tags = NULL;
629                         kfree(tags);
630                         tag_desc++;
631                 }
632                 kfree(mm->context.tag_store);
633                 mm->context.tag_store = NULL;
634         }
635 }
636 

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